Åk 6–9
 
English/Русский
2.4 Algebraic Expressions
Finally, we will write the problem as an algebraic expression. An algebraic expression contains at least one variable. Imagine that we don’t know how many goals Hanna Ljungberg made, then the number of goals is the unknown number, a variable. You usually write this as a letter in mathematics. You may have heard that you can use the letter x, by you can really use whichever letter you wish. We will fill in the example below:


Exemple 1:


Words
Marta made three goals more than Hanna Ljungberg.



Foto: Umeå IK
Pictures


In this figure, you can see that Marta made as many goals as Hanna Ljungberg and the three more.


Tables
We take a few examples where we start from how many goals Hanna Ljungberg made.  Then you can easily calculate how many goals Marta made. It can look like this:


Algebraic expressions
If we don’t know how many goals Hanna Ljungberg made, we can like we wrote in the beginning us a letter. It can look like this:



When we then see that we can figure out how many goals Hanna Ljungberg made then we can exchange x for a number and even calculate how many goals Marta made. As long as we don’t know this then we express it as an algebraic expression.




Exemple 2:

Words
Jasmine worked in the summer as a landscaper.  One day she was asked to plant 10 follows in a row. In every row there was to be three flowers.

How many flower did Jasmine plant?

Pictures



In the figure you see three flowers in ten rows.



Tables
This is the way it woud look in a table which shows the number of rows and total number of flowers:


Algebraic expressions
If you don’t know how many rows she should plant, then you should write this variable with a letter.  We can then use the letter r (you can choose whatever letter you wish).

In the question box below you can find the answer for how this algebraic expression should look.